To distribute recommendation information corresponding to characteristics of a user, the Content-based Filtering method has been developed as an information filtering method for extracting the recommendation information. In the method, when a user takes an action such as browsing a Web page, the browsed subject document is analyzed and words (key words) included in the document are extracted. These words are then distinguished by each user and recorded as interest and preference information that is referred to as a user profile. A concept of an interest is expressed in the user profile, and a method for providing information to a user by using the concept has been developed. A system in that an appropriate advertisement can be recommended by matching keywords assigned to an advertisement product or the like and a user profile (that is expressed by the keywords) is generally known, for example.
Technologies associated with the above include the technology that is described in Patent Document 1. Patent Document 1 discloses a technology in that customers to whom recommendation information is to be distributed and recommendation information to be distributed are determined according to predetermined recommendation extraction rules and that the information is then distributed accordingly.